Should i be able to get a gumpick under a crown? recent fistula and docs trying to figure out which tooth it is.

Simple Solution: Have your dentist take a piece of gutta percha and insert it into the fistula. Once completely seated, have the dentist take a radiograph of the tooth. The gutta percha will show up on the film with the deepest tip resting on the problematic area.

Fistula: No, a gum-pic should not be insertable under a crown. Dentist should be able to trace fistulous tract. If not, see an Endodontist.